linq to entities group by expression给出“匿名类型投影初始值设定项应为简单名称或成员访问表达式”

我用这个表达式得到上面提到的错误:

var aggregate = from t in entities.TraceLines
    join m in entities.MethodNames.Where("it.Name LIKE @searchTerm", new ObjectParameter("searchTerm", searchTerm)) on t.MethodHash equals m.MethodHash
    where (t.CallTypeId & (int)types) == t.CallTypeId && t.UserSessionProcessId == m_SessionId
    group t by m.Name into d                                                   
    select new
    {
        d.Key,                                     
        d.Sum(x => x.InclusiveDurationMilliseconds) // <- squigglies on this line
    };

知道是什么导致了这个错误吗?